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Shure & CD-4 Dear Sir: I would like to comment on Edward Canby's most interesting and provocative article on phonograph cartridges in the June issue of AUDIO. Since he has raised several very pertinent questions regarding the future direction of cartridge development, I would like to answer those questions insofar as possible. Shure's position is that we will provide the best quality cartridge for all record formats that are produced. We will certainly endeavor to satisfy the requirements of the CD-4 system, as well as the matrix and standard stereo. This does not mean, however, that we--or other cartridge manufacturers--can produce a single cartridge that will be the ultimate solution for all systems. It may be that several cartridges will be required, each being the optimum for a given system. In the case of the V-15 III, our objective was to provide the finest phono cartridge possible for the present-day standard stereo disc. This does not mean that we intend to ignore the CD-4 system or any other system. It simply recognizes the fact that the number of CD-4 discs available today is miniscule compared to the millions of standard stereo discs that have been produced over the past 16 years. Even today, the Schwann catalog of records shows approximately 30K stereo discs and certainly fewer than 30 CD-4 discs. The V-15 III has been optimized to satisfy the requirements of the standard stereo disc. The V-15 III will track most present-day records at 3/4 gram. Cartridges being sold for operation with the CD-4 system are specified at two grams. The design of a cartridge that will play satisfactorily at 3/4 gram is significantly different from that which will play at two grams. We feel that the lower tracking force is an extremely important feature of a top-quality stereo cartridge. We have run extensive life tests, which show that the life of a diamond tip increases exponentially as tracking force decreases, as long as the cartridge tracks properly. For cartridges in the price range of the V-15 III, we believe that extending the life of the stylus is a feature we owe to our customers. We could not, therefore, countenance a change in the design of the V-15 III that would require a higher tracking force. In this article, Mr. Canby indicates that the cartridges designed for the CD-4 system are flat in frequency response out to 45,000 Hz. We have tested all of the CD-4 cartridges that we have been able to find, not only for sale in the United States but in Japan and Europe as well. All of these cartridges have a rise in frequency response above about 15 kHz, with a peak in the 25 to 30 kHz region, approximately 10 dB above the 1 kHz level; however, cartridges with such a frequency response can and do work with the CD-4 decoders that we have used for test purposes. On the other hand, we have found that there are numerous other factors that can affect the ability of the cartridge to work with the CD-4 system; but the response, such as I have just described, is satisfactory. The frequency response I have described indicates a major resonance in the 25 to 30 kHz region. A flat frequency response out to 45 kHz would require either a major resonance beyond 45 kHz, or a very highly-damped stylus system. Both possibilities would require a dramatically different approach from that of present-day cartridges. Most probably, successful CD-4 cartridges will show a resonance around 30 kHz, with a fairly significant peak. In order to provide proper trackability for these cartridges, a tracking force in the two-gram region is indicated. One of the problems in developing a cartridge for the CD-4 system is that the system itself is still undergoing development and improvement. In the case of stereo, once the Westrex cutter had been introduced, people produced stereo records; and the phonograph cartridge was designed to satisfy a reasonably fixed objective. In the case of CD-4, there have been numerous improvements in the technique of mastering the records and also in the electronic circuitry for decoding the signal. There also have been changes in the record materials. Designing a cartridge to satisfy the requirements of the CD-4 system, as well as the ear of the trained high-fidelity listener, is not a static task. We believe that it is necessary to produce a cartridge designed specifically for the CD-4 system. At the present state of the art, such a cartridge will be able to perform adequately with standard stereo records; however, we do not believe such a cartridge can approach the ultimate in reproduction of standard stereo records. For such reproduction, we offer the V-15 III. Perhaps, some day in the future, the qualities of these two cartridges may be combined and the ultimate may be offered for both systems simultaneously. Until then, we feel that individual cartridges optimized to satisfy each system should be provided. -James H. Kogen Vice President Shure Bros., Inc., Evanston, Ill. A New Recruit Dear sir, I have been buying your magazine off the newsstand for some time now. I have always thought it was the best. The June and July issues, however, were so good that I was moved to send for a subscription. The July articles about four-channel by Len Feldman, Ben Bauer, and Harry Maynard really sold me on AUDIO. I have a four-channel system and love it. Keep up the good job. -Harry L. McDonald, Takoma Pk., Md. Al Stewart's Instrumentation Dear sir, Mr. Canby's review of my album ( Museum of Modern Brass) just came to my attention. I'm delighted that you felt about it as you did as well as taking the time to write about it in AUDIO. The instrumentation of the group is 5 trumpets, each also playing flugelhorn and piccolo trumpet where called for in the arrangements. The low horns are tuba, bass trombone and French horn, and the six rhythm are keyboard (piano, organ, harpsichord, celeste, electric piano), fender, two guitars, percussion and drums. I hope that the next album grooves you as much as this one did. Thanks for a beautiful article. - Al Stewart, New York, N.Y. Master Tapes Dear sir, In a recent issue of AUDIO in the "Dear Editor" section, I note that Mr. J. E. Cade of Casonic Foundation and Mr. Lee Kuby of Harman-Kardon are looking for prime quality tape dubbings. I have many high quality master tapes available, almost all of which were recorded by myself, at live concerts. Most of the masters were done with the help of the Dolby B system. I use Sony C-500, Neumann U-87, and Vega S-10 condenser mics. I can honestly say that the tapes are extremely good. Most of the performances were done by excellent groups and include a wide variety of music from full symphony to pipe organ (both classical and theatre types) to jazz, etc. I also am looking for dubbings of first rate material that is technically excellent, and I trade tapes with others in this country who are in my position. We all are disgusted with the commercially available source material, and the only way to really get first-rate stuff is to do it ourselves. I would be willing to make duplication of some of my tapes for worthy causes or for trade. I would be pleased if you would refer my name to others who might have prime source material available for my use. Thank you. -Roger Sanders, 1578 Austin St., Atwater, Calif. 95301 Separate Decoders Dear sir, I read with great interest the Leonard Feldman article, "Evolution of Four Channel Equipment." He makes a number of interesting points, although I take minor exception to certain ones. My own four-channel interest predates his "Phase One" by several years since I have previously used a rear speaker wired similar to the Dynaco method to improve the sound field. The present system includes separates across the board. AR3a speakers (the LST is planned for the front), Crown International and SWT Co amplifiers, decoders in profusion (Sansui QS-1, EVX44, Metrotec, JVC-CD4, etc.), 2and 4-channel tape decks, along with numerous other goodies. All of this tied together through a self-designed and built switch panel. I purchase and try new decoders as they come along. (The Sony SQD-2020 is on order.) I gather from Mr. Feldman's article that the trend will be toward an "all in one" sort of box with a demise of the separate decoder. I would not wish to see that day arrive. The receiver has not been built, 4 channel especially, that will match the quality and power of a Crown DC-300, or for that matter, a SWTCo Universal Tiger. A 20 watts per channel receiver simply will not handle an AR3a. If the purist (or in my case, HiFi nut) wants the best, separates is the only way to go, and this means separate decoders. This method will permit any change, modification, up-date or what have you without regard to form factor, power requirement, or visual esthetics decreed by the XYL for her front room. Yes, my system looks like Fig. 3 on page 32, only more so, thank goodness. I can add, use, experiment with any decoder in any format, in any size without disrupting in any way the remainder of the system. I, for one, hope the separate demodulator/decoder is here to stay. -Frank C. Smith APO San Francisco From Radio Shack Dear sir, We are greatly appreciative of the excellent reports on Realistic receivers Len Feldman has written for AUDIO--keep 'em coming! There is just one thing that bugs me: at the end of your STA120 report and the beginning of your QTA-790 report, you commented adversely upon a little stock paragraph on the inside cover of our operational manuals. I wrote that gem about seven years ago merely to indicate Radio Shack's desire to please people via the sound, the look, the feel, and the reliability of our equipment as opposed to mere specs. I have now rewritten those comments out of fear that the next time you review us your irritation will have reached the point of making a headline (or indeed an entire report) out of my innocent prose. Oh, the awesome power of the press! -Lewis F. Kornfeld, Jr., President Radio Shack (Source: Audio magazine.) Also see: = = = = |
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